The lumbar spine of a child with a bulge may be a normal phenomenon, or may be abnormal phenomenon. Newborn baby lumbar spine is soft, no curvature or only a slight convexity, 3 months when the child’s neck and back muscles gradually strengthened, the spine also began to form the first physiological curvature of the cervical vertebrae anterior convexity. At 6 months of age, the child does not need external support, will form the second physiological curvature of the thoracic spine, and 1 year of age will appear to form the third physiological curvature of the lumbar spine anterior convexity, lateral position shows that the lumbar spine forward convexity. This kind of physiological curvature is a normal phenomenon. Children have lumbar bulge also have abnormal phenomenon, children do not correctly sit and sleep and other bad habits will cause lumbar bulge, daily lumbar pressure to bear too much, lumbar trauma or lumbosacral deformation vertebrae will squeeze lumbar vertebrae, resulting in lumbar deformation or bulge, then children will have localized pain, serious pain, and the lumbar spine will not be able to move. At this time, the child will appear localized pain, serious nerve pain, this situation is not normal. In summary, the child lumbar bulge has normal phenomenon and abnormal phenomenon, if the child grows up in the process of abnormal bulge, go to the hospital in a timely manner.